1. Field of Invention
The present invention relates to attaching a pressure sensitive skin adhesive only to the inside of a partly or fully cured silicone raw urisheath or on other cured elastomer or thermoplastic elastomer raw urisheaths by using a total or selective oxidative corona, plasma, flame treatment; or UV, E-beam or gamma-irradiation; or chemical oxidative treatment; or by using a silicone tie-layer.
2. Description of the Prior Art
External urinary catheters are conventionally used in urinary catheter devices for aiding male urinary incontinence and for use in hospitals in connection with treatment and surgery of urethral disorders. Such an external urinary catheter normally comprises a sheath or body portion, such as a tubular body, enclosing the shaft of the penis, and a tip portion that is provided with a comparatively short discharge tube, which via a hose is connected to a urine collection bag that is e.g. fastened to the bed or the leg of the user.
Traditionally, the external urinary catheter is delivered in a rolled-up condition. In this delivery condition, the sheath portion is rolled-up in a number of successive windings to such an extent that the layer of adhesive is entirely accommodated in the windings to allow the urisheath to be packaged and handled without the inner side of the sheath portion adhering to the surroundings. In order to apply the external urinary catheter on a penis, the sheath portion is unrolled slightly until the layer of adhesive on the inner side of the sheath portion is exposed. In this condition, the external urinary catheter is positioned on the penis such that the layer of adhesive is brought into contact with the skin and the remaining part of the sheath portion is subsequently unrolled.
Silicone is considered to have good properties for making urisheaths. The main problem about using it is attaching an adhesive securely to the inside of the urisheath, and at the same time being able to unroll the urisheath easily for the user. It has been considered very difficult to attach an adhesive to a ready-made silicone raw urisheath, because silicone materials inherently are release materials for all other pressure sensitive adhesives than silicone adhesives.
U.S. Pat. No. 5,176,666 describes how to adhere a pressure sensitive adhesive to a dipped silicone urisheath. The adhesion is done by dipping a non-cured silicone urisheath on a dipping mandrel where adhesive has already been applied and stripped to the right length, and then curing the silicone on the mandrel with adhesive. The aforementioned process secures at least a physical binding between the silicone and the adhesive.
U.S. Pat. No. 5,779,964 describes how to adhere a pressure sensitive adhesive on an already cured dipped silicone urisheath. This is done by applying the adhesive to the outside of the urisheath, then cure it, and subsequently applying a surface preparation layer on top, which has a greater affinity for the silicone rubber than the adhesive has. By rolling up the urisheath the surface preparation layer comes in contact with the inside of the silicone urisheath, and thereby the adhesive is transferred to the inside of the urisheath together with the surface preparation layer.
Silicone adhesives will be able to attach to a ready-made silicone raw urisheath, but will give the problem of needing to put a special release layer on the outside of the urisheath in order for the silicone pressure sensitive adhesive not to adhere to the outside of the urisheath in the rolled up position.
With all other commonly used pressure sensitive skin adhesives the cured silicone material will give a release effect for the pressure sensitive adhesive, making the adhesive stick to the skin instead of the urisheath when taking the product off after use. With these adhesives the job is, in popular terms, to make the adhesive stick strongly to one side (the inside) of the silicone urisheaths but not to the other (the outside).
There is a need for an alternative way to attach a commonly used pressure sensitive skin adhesives to a partly or fully cured silicone raw urisheath.